This is phishing; criminal act of testing your number to see if it's worth selling to other criminals.  Once they have a victim, that number gets sold and published to millions of scammers; don't fall for it, these are criminals - plain and simple.  Don't release/confirm/deny ANY information.  Better yet, don't answer.   Best advise - block the number(s), report it to the FCC site, share and stay informed.